JP2009176798A - Light-emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a matter that the screen of car navigation becomes hard to view from an oblique direction, i.e. the direction that an operator or a fellow passenger actually views the screen, when a light-emitting device is used as a backlight of the screen of car navigation because emission of light from the light-emitting section of a conventional light-emitting device and the peak of intensity by light reflected on a reflective frame are set in the front direction. <P>SOLUTION: A light-emitting device comprises a light-emitting section where a light-emitting element mounted on a circuit board is resin sealed, and a reflective frame being mounted on the circuit board. The angle of reflecting surface of the reflective frame is set such that emission of light from the light-emitting section and the peak of intensity by light reflected on the reflective frame fall in a range of 30°-50° in the right and left direction. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a light-emitting device including a light-emitting element and a reflective frame, and particularly to a light-emitting device considering directivity.

  Currently, a light emitting device including a light emitting element such as an LED and a reflective frame is used as a light emitting device for a backlight in a liquid crystal display device or the like. (For example, refer to Patent Document 1).

  However, the conventional light-emitting device composed of the light-emitting element and the reflective frame is intended to enhance the illumination effect when the display device is viewed from the front side as seen in Patent Document 1, and thus the reflective frame The angle of the reflective surface was set to 40 ° to 50 °, which increased the reflectance in the front direction.

  However, depending on how the display device is used, it is not necessarily viewed from the front side, and there is a growing need for various display angles to be the main display direction, and the conventional reflectance in the front direction has been increased. There is a problem that the light-emitting device cannot cope with it. Hereinafter, the relationship between the light emitting device and the display device in the prior art will be described with reference to the drawings.

  6 and 7 show a light-emitting device constituted by a light-emitting element and a reflective frame in the prior art, and a car navigation using the light-emitting device. FIG. 6 is a front view of a car navigation part of a vehicle, FIG. 7 is a cross-sectional view of a light emitting device as a backlight used for car navigation. In FIG. 6, reference numeral 50 denotes a car navigation screen, which is provided on a display panel 80 positioned between the driver side with the vehicle handle 60 and the passenger side with the storage box 70. Therefore, the angle at which the driver or passenger sees the car navigation screen 50 is not the front direction C of the car navigation screen 50 but the diagonal direction A from the driver side and the diagonal direction B from the passenger side as the main display direction. The angles of the oblique direction A and the oblique direction B are approximately 30 ° to 50 °.

  A light-emitting device 30 including a light-emitting element and a reflective frame in the prior art shown in FIG. 7 is provided as a backlight of the car navigation screen 50 shown in FIG. 6, and includes a circuit board 1 on which an electrode pattern is formed, The light-emitting part 2 formed by resin-sealing a light-emitting element mounted on the circuit board and a reflection frame 5 placed on the circuit board are provided, and light emission P1 (shown by thin lines) of the light-emitting part 2 is provided. And the reflection surface angle of the reflection frame 5 (from the circuit board 1) so that the luminance peak due to the reflected light P2 (shown by a thick line) by the reflection frame 5 is in the front direction (90 ° direction to the light emitting surface). Is set to 40 ° to 50 °.

JP 2004-327955 A

  However, in the light emitting device 30 shown in Patent Document 1, the luminance peak due to the light emission P1 of the light emitting unit 2 and the reflected light P2 from the reflection frame 5 is set in the front direction, so the back of the car navigation screen 50 shown in FIG. When used as a light, the display from the front direction C of the car navigation screen 50 is easy to see, but the display from the oblique directions A and B that are actually seen by the driver and passengers is difficult to see. .

  The object of the present invention is to solve the above problems and provide a light emitting device having directivity characteristics in an optimal direction as a backlight of a display device that a driver or a passenger sees from an oblique direction like a car navigation screen. There is to do.

  In order to achieve the above object, the configuration of the present invention includes a circuit board on which an electrode pattern is formed, a light emitting part formed by resin-sealing a light emitting element mounted on the circuit board, and placed on the circuit board. In the light emitting device including the reflective frame, the reflection surface angle of the reflective frame is such that the luminance peak due to the light emitted from the light emitting unit and the reflected light from the reflective frame is 30 ° to 50 ° in the left-right direction. It is characterized by comprising.

  According to the above configuration, since the directional characteristic of the light emitting device is a heart-shaped backlight having a peak at 40 ° to 50 ° in the left-right direction, oblique directions A and B that are actually seen by the driver and passengers. It has the effect of making the display from easy to see.

  The angle of inclination of the reflection surface of the reflection frame is 70 ° to 80 ° when viewed from the horizontal direction.

  The light emitting unit has an outer shape with a horizontal upper surface.

  The light emitting section is composed of a blue light emitting diode element and a phosphor-mixed resin that seals the blue light emitting diode element.

  The light emitting unit includes three types of light emitting diode elements including red, green, and blue.

  As described above, in the present invention, since the directional characteristic of the light emitting device is a heart-shaped backlight having a peak at 40 ° to 50 ° in the left-right direction, the oblique direction that is actually viewed by the driver or passengers The display from A and B has the effect of being easy to see.

  Hereinafter, light emitting devices according to embodiments of the present invention will be described with reference to the drawings. 1 to 5 show a light-emitting device according to an embodiment of the present invention. FIG. 1 is a perspective view of the light-emitting device, FIG. 2 is a cross-sectional view taken along the line AA of the light-emitting device shown in FIG. FIG. 4 is a cross-sectional view of a light-emitting device showing a change in the reflection surface angle of the reflection frame, FIG. 4 is a cross-sectional view of the reflection frame showing typical reflection forms, and FIG. 5 is a characteristic showing the invention characteristics in each reflection form shown in FIG. 3 and 4, the basic configuration of the light emitting device shown in FIGS. 3 and 4 is the same as that of the conventional light emitting device shown in FIG. 7, and the same elements are denoted by the same reference numerals and redundant description is omitted.

  FIG. 1 is a perspective view of a light emitting device 10 according to the first embodiment of the present invention, and a car navigation screen 50 is indicated by a dotted line. In the light emitting device 10, the light emitting unit 2 is mounted on the central portion of the circuit board 1, and the reflection frame 5 is fixed on both sides of the light emitting unit 2. 2 is a cross-sectional view taken along line AA of the light-emitting device 10 shown in FIG. 1, and a plurality of blue LEDs 3 are mounted in the longitudinal direction of the light-emitting portion 2, and the plurality of blue LEDs are mixed with fluorescent particles. 4, this light emitting portion 2 constitutes a known white light emitting portion. The light emitting device 10 differs from the conventional light emitting device 30 shown in FIG. 7 in the angle of inclination of the reflecting surface 5a of the reflecting frame 5 from the surface of the circuit board 1, and the reflecting surface of the conventional light emitting device 30. While the inclination angle θb of 5a is 40 ° to 50 °, the inclination angle θa of the reflecting surface 5a of the present invention is 70 ° to 80 °, which is steep.

  Next, the relationship between the inclination angle θ of the reflection surface 5a in the reflection frame 5 of the light emitting device and the reflected light angle α will be described with reference to FIG. FIG. 3 shows the relationship between the angle of reflection θ of the reflecting surface 5a and the angle of reflected light α from the reflecting surface 5a when the angle of inclination θ of the reflecting surface 5a is changed from 40 ° to 90 ° at intervals of 10 °. 10A shows that the reflected light angle α of the reflected light P2 indicated by a thick line is 110 ° when the inclination angle θ is 40 °, and similarly, FIG. 10B shows the inclination angle. When θ is 50 °, the reflected light angle α is 90 °, (C) is reflected when the tilt angle θ is 60 °, the reflected light angle α is 70 °, and (D) is reflected when the tilt angle θ is 70 °. The light angle α is 50 °, (E) is the reflected light angle α is 30 ° when the tilt angle θ is 80 °, and (F) is the reflected light angle α is 10 ° when the tilt angle θ is 90 °. It is shown that.

  Next, the light emission characteristics at the oblique angle θ in the light emitting device 10 will be described with reference to FIGS. FIG. 4 is a cross-sectional view of the light emitting device 10 showing a relationship between a representative inclination angle θ of the reflection surface 5a in the reflection frame 5 and the reflected light angle α, and FIG. 4A is a case where the reflection frame 5 is not provided. The light emission form, (B) is the light emission form when the inclination angle θ is 50 °, and (C) the light emission form when the inclination angle θ is 70 °. 4B corresponds to FIG. 3B, and FIG. 4C corresponds to FIG. 3D.

  FIG. 5 is a light emission characteristic diagram in each light emission form of the light emitting device 10 shown in FIG. 4, and the light emission characteristic Ha is a light emission characteristic in the light emission form in the case where the reflection frame body 5 in FIG. Since it does not exist, it becomes a horizontally long elliptical shape only by the light emission P1. The light emission characteristic Hb is a light emission characteristic in the light emission form when the inclination angle θ of the reflection frame 5 in FIG. 4B is 50 °, and the reflected light P2 exists in the direction of the reflected light angle α of 90 °. , A vertically long ellipse having a peak in the 90 ° direction. Furthermore, the light emission characteristic Hc is a light emission characteristic in the light emission mode when the inclination angle θ of the reflection frame 5 in FIG. 4C is 70 °, and the reflected light P2 exists in the direction of the left and right reflected light angles α of 50 °. In addition, it has a heart shape having two peaks in the left and right directions of 50 °.

  From the light emission characteristics shown in FIGS. 4 and 5, the light emission characteristic Ha in the light emission form without the reflection frame body 5 in (A) has a low illumination effect on the car navigation screen 50, and the reflection frame in (B). The light emission characteristic Hb in the light emission form when the inclination angle θ of the body 5 is 50 ° has a high lighting effect in the front direction of the car navigation screen 50, that is, the front direction C shown in FIG. 6, but the oblique direction A from the driver side. It can be seen that the illumination effect in the oblique direction B from the passenger side is low. On the other hand, the light emission characteristic Hc in the light emission mode when the inclination angle θ of the reflection frame 5 in (C) is 70 ° has a little illumination effect in the front direction of the car navigation screen 50, that is, the front direction C shown in FIG. Although it is low, it turns out that the illumination effect of the diagonal direction A from a driver | operator side and the diagonal direction B from the passenger side is high.

  The relationship between the light emission P1 and the reflected light P2 in FIG. 4C and the light emission characteristic Hc shown in FIG. 5 is as follows. 5 constitutes the right peak Hcr of the light emission characteristic Hc shown in FIG. 5, and the left peak Hcl of the light emission characteristic Hc is constituted by the combined light of the reflected light P2 and the light emission P1b from the right reflecting frame 5r. Has been.

  As for the height of the reflection frame 5, if the height of the reflection frame 5 is too high, the reflected light P <b> 2 once reflected by the left reflection frame 5 l is reflected again by the right reflection frame 5 r. Thus, the repetition of the reflection deforms the shape of the light emission characteristic Hc shown in FIG. 5 to deteriorate the illumination effect. Therefore, in order to obtain a normal heart-shaped characteristic, the reflection on the reflection frame is reflected only once. It is necessary to determine the height so that light enters the display device.

  As described above, in the present invention, in the display device in which the direction viewed by the driver and passengers is not the front direction of the car navigation screen, but the diagonal direction is the main display direction as in the car navigation screen, It has been found that an easy-to-view screen can be constructed by making the reflection angle of the reflection frame in the light emitting device of FIG. Further, in the embodiment, the configuration in which the directivity characteristics of 50 ° to 40 ° are obtained by setting the reflection angle of the reflection frame to 70 °, but the reflection angle of the reflection frame is set to 80 ° as a slightly steep angle. However, it has been found that a heart-shaped light emission characteristic having directivity characteristics of peaks Hcr and Hcl can be obtained at 40 ° to 30 °, which is slightly lowered, and the light emission device is effective as a backlight of a car navigation screen.

  Moreover, although the white LED which coat | covered blue LED with the fluorescent resin 4 which mixed the fluorescent particle was illustrated as a structure of a light emission part, it is not limited to this, As a structure of a light emission part, from red, green, and blue A light source such as a white LED in which the three-color LED elements are covered with a transparent resin or electroluminescence can be used.

  As mentioned above, although embodiment which uses the light-emitting device in this invention as a backlight of a car navigation screen was shown, it is not limited to this, For example, a player sees from both sides like a display screen of a battle-type game machine All screens can be used.

It is a perspective view of the light-emitting device in this invention. It is AA sectional drawing of the light-emitting device shown in FIG. It is sectional drawing of the light-emitting device which shows the change of the reflective surface angle of the reflective frame body in this invention. It is sectional drawing of the reflection frame which shows the typical reflection form of this invention. It is a light emission characteristic view in each light emission form of the light emitting device shown in FIG. It is a front view of the car navigation part of the conventional vehicle. It is sectional drawing of the light-emitting device as a backlight used for the conventional car navigation.

Explanation of symbols

1 Circuit board 2 Light emitting part 3 Blue LED
4 Fluorescent resin 5, 5 r, 5 l Reflective frame 5 a Reflective surface 10, 30 Light emitting device 50 Car navigation screen 60 Handle P1 Light emission P2 Reflected light

Claims (5)

  In a light-emitting device including a circuit board on which an electrode pattern is formed, a light-emitting unit formed by resin-sealing a light-emitting element mounted on the circuit board, and a reflection frame body placed on the circuit board, The light emitting device according to claim 1, wherein the reflection surface angle of the reflection frame body is configured so that a luminance peak due to light emitted from the light emitting unit and light reflected by the reflection frame body is 30 ° to 50 ° in a horizontal direction.   The light emitting device according to claim 1, wherein an angle of inclination of the reflecting surface of the reflecting frame is 70 ° to 80 ° when viewed from the horizontal direction.   The light-emitting device according to claim 1, wherein the light-emitting portion has an outer shape with a horizontal upper surface.   The light emitting device according to any one of claims 1 to 3, wherein the light emitting unit includes a blue light emitting diode element and a phosphor-mixed resin that seals the blue light emitting diode element. The light emitting device according to any one of claims 1 to 4, wherein the light emitting unit includes three types of light emitting diode elements including red, green, and blue.

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